A hybrid-electric or all-electric vehicle includes one or more electric machines that are used for vehicle propulsion. The electric machines operate with relatively large voltages and currents when compared to a traditional 12 Volt vehicle power system. A high voltage system may monitor the connection status of the electric machines. A typical electric machine may be a three-phase motor and include connection of three conductors between the electric machine and a power inverter. To monitor the connection status, an additional low-voltage signal line is often included between the power inverter and the electric machines. The additional low-voltage signal is monitored to ascertain the connection status between power inverter and the electric machines.